Pentachlorophenol (PCP) is a highly toxic biocide used throughout the United States as a preservative and pesticide. About 5 X 10 to the 7 Kg year-1 of PCP are produced world wide, with about 2.3 x 10 to the 6 Kg of that being produced in the U.S. PCP has become a general contaminant of our environment, with contamination of soils, sediments, surface waters, and ground waters being common. Bacteria degrade PCP, but little is known of the biochemistry and genetics of the biodegradative process. We propose to elucidate the fundamental mechanisms of bacterial PCP degradation. We will use chemostats to enrich pure cultures of PCP-degrading bacteria. We will identify our cultures using standard techniques of bacterial taxonomy. We will elucidate the catabolic pathways employed by our cultures for degradation of PCP. We will use primarily enzymological analyses of catabolic enzymes (monooxygenases, dioxygenases, dehalogenases, etc.) and high-resolution 13C-NMR spectroscopy techniques during this part of the project. All PCP-degrading bacterial strains will be examined for the possible presence of plasmids encoding the PCP-degrading phenotype. Certain catabolic enzymes will be purified.